The present invention relates to an oxygen sensor for detecting the concentration of oxygen in gas under measurement (such as automotive engine exhaust gas) and, more particularly, to a method and apparatus for quality inspection of the oxygen sensor and a method for production of the oxygen sensor.
Japanese Laid-Open Patent Publication No. 2005-201840 discloses an oxygen sensor that includes a substrate portion, a sensing portion disposed on the substrate portion and having an oxygen ion conducting solid electrolyte layer and a pair of inner and outer electrodes on opposite sides of the solid electrolyte layer and a protector fixed to the substrate portion so as to surround therein the sensing portion. The sensing portion is generally prepared by printing the inner electrode on the substrate portion, printing the solid electrolyte layer on the inner electrode, printing the outer electrode on the solid electrolyte layer, and then, sintering the printed laminate of the solid electrolyte layer and inner and outer electrodes at temperatures of 1400 to 1500° C.